The "unallocated" portions happen sometimes... not 100% sure why. You could extend a partition to encompass the 470MB on the right.... but the one on the left is a little tougher.
Disk Management won't (shouldn't) let you extend C over the 501MB on the left.... so third party tools would be required.
As for the recovery partition..... yes, you should leave that alone. As it's labelled, it's for recovery purposed (and I believe holds the boot partition too). Any Windows 10 install will have those two, and is perfectly normal.